A widely-used method for manufacturing a laminated core is, for example, laminating iron core pieces with a thickness of 0.3 mm or less, and joining the iron core pieces by caulking, welding and the like. However, when iron core pieces are joined by caulking and welding, there is a problem in that the iron core pieces become conducted in a laminating direction, which generates eddy-current loss and lowers motor function.
In order to solve this problem, as illustrated in FIGS. 13(A) and 13(B), there is a method for manufacturing a laminated core 93 in which iron core pieces 90 are joined by injecting resin 92 in respective resin holes 91 and curing the resin, the resin holes 91 being formed by a plurality of through-holes provided to the iron core pieces 90 and made to be communicated in a laminating direction. Since the resin 92 is an insulator, the neighboring iron core pieces 90 do not become conducted, which prevents the generation of eddy-current loss (See Patent Literature 1).